Apparatus for preparing protected metal sheets



July 26, 1966 VUKOVCAN ET AL 3,262,192

APPARATUS FOR PREPARING PROTECTED METAL SHEETS 2 Sheets-Sheet 1 FiledAug. 1, 1965 QMSEEQ N INVENTORS R0004 PA! L. VUAOl/CA/V,

0,4100 BAR/P BY DOA/ALD /r. A/acw R. L. vUKovcAN ETAL 3,262,192

2 Sheets-Sheet 2 ZTMEA ATL July 26, 1966 APPARATUS FOR PREPARINGPROTECTED METAL SHEETS Filed Aug. 1, 1963 United States Patent "ice3,262,192 APPARATUS FOR PREPARING PROTECTED METAL SHEETS Rudolph L.Vulrovcan, Ambridge, Donald K. Archer, Pittsburgh, and David Barr,Leetsdale, Pa., assignors to H. H. Robertson Company, Pittsburgh, Pa., acorporation of Pennsylvania Filed Aug. 1, 1963, Ser. No. 299,326 6Claims. {(129-200) This invention relates to apparatus for producing aprotected metal article, more particularly a protected metal buildingsheet. Protected metal building sheets have been described in US.patents of Alden W. Coffman 2,073,334, 2,631,641 and 2,764,808, interalia.

The object of the present invention is to provide improved apparatus forfabricating long lengths of protected metal building sheets efficientlyand economically.

In the accompanying drawings:

FIGURE 1 is a cross-sectional view of a typical protected metal articleof the type described in the aforementioned U.S. Patents 2,073,334,2,631,641 and 2,764,- 808;

FIGURE 2 is a schematic illustration of apparatus similar to that shownin the aforementioned US. Patents 2,631,641 and 2,764,808 for preparingprotected metal sheets in long coiled strips;

FIGURE 3 is a fragmentary side-elevation illustration of a crown roll inengagement with a molten-coated metal sheet moving through the presentprocesssing sequence;

FIGURE 4 is a cross-section view taken along the line 4-4 of FIGURE 3showing the crown roll and metal strip in normal relationship;

FIGURE 5 is a fragmentary plan view taken along the line 5--5 of FIGURE4 showing the crown roll and metal strip in normal relationship;

FIGURE 6 is a cross-section view similar to FIGURE 4 showing the crownroll displaced from its normal position to accommodate displacementtendencies of the metal strip;

FIGURE 7 is a fragmentary plan view similar to FIG- URE 5 showing thecrown roll displaced from its normal position to accommodatedisplacement tendencies of the metal sheet;

FIGURE 8 is a fragmentary perspective illustration of a spring-mountedroller element and its associated measuring means.

Protected metal sheets A protected metal sheet 10 is shown in FIGURE 1,comprising a metal sheet core 11, a coating of adhesive non-corrodiblemetal 12 and an outer fibrous layer 13. The metal core 11 is formed fromiron or steel, from about 14 gauge to about 28 gauge thickness,prefer-ably from about 18 gauge to about 26 gauge thickness. Eithercold-rolled or hot-rolled steel sheets are suitable. The non-corrodibleadhesive metal coating 12 is preferably zinc, although various zincalloys are acceptable as well as tin, cadmium, lead or othernon-corrodible metals or alloys. The adhesive coating 12 becomes alloyedwith the metal core 11 during the fabrication of the protected metalsheet 10.

The adhesive metal coating 12 is afiixed to the metal core 11 usually bya hot dip process wherein a film of molten adhesive coating metal isapplied directly to the entire outer surface of the metal core. Whilethe adhesive coating remains molten, the fibrous layers 13 are pressedinto the molten adhesive coating whereby the layers become mechanicallykeyed or anchored to the resulting protected metal sheet 10. Theforegoing processing technology is described in the aforementioned USPatent 2,073,334. Subsequently the fibrous layers 13 are impregnatedwith a resinous or bituminous saturant which pro- 3,262,192 PatentedJuly 26, 1966 vides weather-resistant properties for the resultingbuilding sheet.

Apparatus and methods for continuously producing such protected metalsheets are described in the aforementioned US. Patents 2,631,641 and2,764,808. These two patents describe a critical feature in thesuccessful fabrication of protected metal sheets, to wit, the transferof the metal coated sheet from a hot-dip galvanizing bath to a set ofopposed bonding rolls where the fibrous coating is pressed against themolten adhesive metal. Generally those patents recommend verticalwithdrawal of the metal core sheet from the galvanizing bath followed byvertical passage of the core sheet between horizontally aligned bondingrolls.

According to the present invention, the metal coated sheet is deliveredfrom the hot-dip galvanizing bath over crown roll means and thenceslopingly upwardly to vertically aligned bonding rolls.

This delivery attitude differs from the prior art which shows either (a)generally vertical travel of the coated metal sheet between thegalvanizing pot and the horizontally aligned bonding rolls (US.2,764,808 and US. 2,631,641) or (b) a generally horizontal travel of thecoated metal sheet prior to entry into the nip of vertically alignedbonding rolls (US. 2,714,246; 2,724,177; 3,077,- 032). It is notcontended herein that the mere change in attitude of the sheet deliveryconstitutes any invention. Nevertheless, those workers in the prior artwho have proposed apparatus and methods for continuous strip processinghave uniformly proscribed direction changes of the metal strip betweenapplication of the molten metal adhesive coating and the nip of thebonding rolls. Providing a direction change of the metal sheet betweenthe galvanizing pot and the nip of the bonding rolls is contrary to theexpress teachings of the art of continuous fabrication of protectedmetal.

In the actual fabrication of continuous lengths of protected metal,however, one serious difiiculty has been maintaining alignment of thefibrous layers with the galvanized metal core. Minor changes inalignment of the moving metal core throughout the sequential processingapparatus are magnified as the metal core progresses through the system.The result is misalignment of the metal core at the nip of the bondingrolls whereby one edge portion of the resulting protected metal sheetdoes not receive a fibrous layer covering.

The present invention presents a solution to the bonding rolls alignmentproblem in the fabrication of such protected metal sheets.

Typical processing apparatus is presented in FIGURE 2 wherein a coil 19vof metal core sheet 20 is positioned in uncoiling attitude at the entrypoint of a sequential processing system. The coil 19 preferablycomprises a sheet 20 of cold-rolled steel or hot-rolled steel having athickness from about 18 gauge through about 26 gauge. The metal coresheet 20 is delivered sequentially through a degreasing bath 21, apickling bath 22, a water rinse bath 23, a galvanizing pot 24, a heatingfurnace zone 25, a pair of vertically aligned bonding rolls 26a, 26b,additional processing apparatus hereinafter described to a take-up coil27.

Drive means such as sheet-engaging rollers 29, 30 are provided for themetal core sheet 20 between the coil 19 and the galvanizing pot 24. Therollers 29, 30 may be driven in synchronism by a suitable motive powersource such as an electric motor 31.

The galvanizing .bath 24 comprises preferably a container having aninventory of molten heating metal such as lead 32, a supernatant layerof molten flux 33 on one side of a vertical baflie 34 and a supernatantlayer of the molten adhesive metal 35 on the other side of the verticalbaffle 34. A pair of exit rolls 36 is partly immersed in the moltenadhesive metal 35 to regulate the thickness of adhering molten metal onthe metal core sheet 20a.

After the metal core sheet 20 leaves the galvanizing pct 24 it is coatedwith a molten adhesive metal and is identified by the numeral 20a. Afterthe coated metal core sheet 20a passes through the nip of the bondingrolls 26a, 21b, it is coated with fibrous layer 40a, 40b provided fromthe coils 28a, 28b and is identified by the numeral 20b. After thefibrous coated metal core 20b has become impregnated withweather-resistant saturant, it is identified by the numeral 20c.

Emerging from the galvanizing bath 24 in a generally vertical attitude,the coated metal core sheet 20a turns over a guide roll means such as acrown roll 38 which is mounted within a few feet of the exit rolls 36.Beyond the crown roll 38, the metal core sheet traverses a heated zone25 wherein the temperature is sufficient to prevent fusion of the moltenadhesive metal coating. In a preferred embodiment, heating gas is burnedwith air within the heating zone 25 and the resulting fumes andcombustion products are vented through a flue 39. The coated metal coresheet 2011 passes directly unsupported from the crown roll 38 to thebonding rolls 26a, 26b at an angle of 20 to 60' degrees relative to thehorizontal. Sheets of asbestos paper 40a, 40b are withdrawn continuouslyfrom the coils 28a, 28b, respectively. The combustible content of theasbestos paper sheets is burned by impingement with flames identified bythe arrows 41, 42. The sheets of residual incombustible asbestos paperperipherally engage the bonding rolls 26a, 26b respectively and, as theasbestos passes through the nip of the bonding rolls, the moltenadhesive metal coating is substantially concurrently fused and pressedinto the interstices of the asbestos sheets to provide a mechanicalkeying or anchoring of the abestos paper to the metal core sheet. Theresultinglaminated sheet structure is identified by the numeral 20b,

Any excess asbestos paper at the side edges of the laminated sheet 20bis removed by means of trimming devices such as abrasive edge trimmerwheels 43 or spirally grooved steel burrs.

The protected metal sheet 20b is subsequently impregnated with asuitable resinous or bituminous saturant contained in a molten bath 45.The impregnated protected metal sheet passes through a pair of groovedimpregnating rolls 46 and thence through one or more pair ofsmooth-surfaced wiping rolls 47. Excess impregnant is collected in atray 48 beneath the rolls 46, 47 and returned to the molten bath. Thecoated, smooth-surfaced protected metal sheets may be cooled by passingthrough water cooled rolls 49 and water sprays 50.

The resultant impregnated protected metal 20c may be turned into -a coil27 as shown in FIGURE 2 for aging prior to further processing.

The further processing might comprise applying outer coatings of resins,asphalts and the like. The final sheets are cut to desired lengths androlled or bent into desirable architectural shapes.

With the present method and the present apparatus, the angle of thecoated metal sheet 20a as it engages the bonding rolls 26a, 26b isbetween about 20 and 60 with the horizontal. A tray member 37 isprovided beneath the heating zone 25 to collect any dripping moltenmetal and return it directly into the galvanizing pot 24.

The bottom surface of the coated metal sheet 20a thereby engages thebonding roll 26b prior to the engagement of the upper surface with thebonding roll 26a. We have found that the vertically aligned bondingrolls are not thereby subjected to damage from fused adhesive metaldroplets.

The present invention The present invention resides in the region of theprocessing sequence between the galvanizing pot exit rolls 36 and thebonding rolls 26a, 26b, i.e., that portion of the sequence wherein themetal core sheet 20 is coated with the molten adhesive metal and isidentified by the numeral 20a. At the bonding rolls 26a, 26b, two sheetsof the asbestos paper 40a, 40b are presented in alignment for receivingtherebetween the coated metal core sheet 20a.

Accurate alignment of the metal core sheet 20a is necessary in order toachieve total surface coverage of the fibrous layers. The crown roll 38is mounted in a controllably adjustable fashion as indicatedschematically in FIGURE 3 wherein the crown roll is seen to be mountedin bearing blocks 51 which are mounted in a suitable housing to permitrapid adjustment of the roll axis location both horizontally (the arrowsA) and vertically (the arrows B). The crown roll 38 possessescircumferential grooves 53 which serve to distribute the molten metalcoating over the undersurface of the metal sheet 20a which contacts thesurface of the crown roll 38.

The position of the crown roll 38 determines the presentation of thecoated metal sheet 20a at the nip of the bonding rolls 26a, 26b. Thecrown roll 38 and the coated metal sheet 20a are shown in FIGURES 4 and5 in their normal relationship, i.e., with the bearing blocks 51 of thecrown roll normally disposed so that the axis 52 of the crown roll ishorizontal and is normal to the direction of travel of the metal sheet20a. FIGURE 6 illustrates the relative displacement of the metal sheet20a on the crown roll 38 as the roll axis 52 is displaced from thehorizontal by the angle Likewise FIGURE 7 shows the relativedisplacement of the sheet 20a and the crown roll 38 as the axis 52 isdisplaced from normal (relative to the travel of the sheet 2011) by theangle 0.

It will be observed that the crown roll 38 has a greater diameter at itscenter than at its ends. By remotely regulating the disposition of thebearing blocks 51, an operator may control the presentation attitude ofthe coated metal sheet 20a at the nip of the bonding rolls 26a, 26b toprovide full fibrous layer covering for the metal sheets 20b- However,we have found that the crown roll 38 is effective only when the coatedmetal core strip 20a is maintained at a predetermined tension as itpasses over the crown roll 38. Unless there is a suflicient tension inthe metal core sheet 20 where its entire bottom surface engages thecrown roll, the operator (of the crown roll) cannot regulate the sheetposition. In accordance with this invention, we have found it to benecessary to maintain the sheet tension at a predetermined value betweenthe bonding rolls 26a, 26b and a selected point along the metal coresheet 20 preceding the galvanizing pot 24.

Specifically, the actual tension in the metal sheet 20 is continuouslymeasured at a measuring station 55 which is located prior to thegalvanizing pot 24 in the processing sequence. The measuring station 55also is located subsequent to at least one of the drive rollers 29, 30in the processing sequence. The measuring station includes means fordetermining the instantaneous tension of the metal sheet 20 andregulating means 72 for accelerating and decelerating the drive motor 31according to the deviation of the actual sheet tension from apredetermined value. A controlling means such as an adjustment knob 73is provided to control the predetermined tension which is to bemaintained. Where the measured sheet tension is excessive, the motormeans 31 is accelerated to relieve the tension; where the measuredtension is insufficient, the drive motor means 31 is decelerated toaugment the sheet tension.

Tests have shown that the system operator can regulate the alignment ofthe metal sheet 20a at the bonding rolls 26a, 26b so long as the tensionof the sheet over the crown roll 38 is maintained at a sufiicient value.The precise value, as might be expected, varies somewhat according tothe sheet width and sheet thickness. Where the back tension isinadequate, adjustment of the displacement of the crown roll 38 has nosignificant effect on the presentation of the metal sheet.

A preferred embodiment of the measuring station 55 comprises aresilient-mounted roller assembly as shown in FIGURE 8 wherein theroller 56 is mounted for rotation in journals 57 which are slidablypositioned within a frame 58 having generally vertical side members 59serving as vertical guideways for the journal 57. A compressed spring 60fits within the frame 58 against a bottom frame member 61 and againstthe journals 57.

The roller 56 is positioned out of the straight-linetravel-path of themetal sheet so that tension of the metal sheet exerts a force componentagainst the roller 56 in a direction which can be resisted by thecompressed spring 60.

An electrical variable control device 62 is rigidly mounted relative tothe frame 58. The electrical variable control device might be asaturable reactor or similar device having an electrical property whichcan be altered in response to a mechanical displacement. A pivotedcompound linkage is provided consisting of arms 63, 64 which are joinedthrough a common pin 65. The other end of the arm 63 is pivotally joinedto the journal 57 by means of a pin 66. The other end of the arm 64 ispivotally secured to a journal 67 which is fixed relative to the frame58 and the control device 62. The arm 64 is equipped with a trackelement 68. The control device 62 has a reciprocal rod member 69 whichhas a roller 70 at its extended end. The roller 70 engages the trackelernent 68.

An electrical impulse conduit 71 extends from the control device 62 tothe regulating means 72 (FIG- URE 2).

As the journal 57 moves downwardly within the frame 58 (in response toincreased tension of the metal sheet), the linkage arm 64 turnscounterclockwise about the fixed journal 67. The track element 68 allowsthe roller 70 and rod member 69 to extend from the control device 62,thereby changing the electrical property of the control device 62 whichis responsive to displacement of the rod member 69.

The altered electrical property of the control device 62 affects theregulating means 72 via the conduit 71 to accelerate the motor 31 (inthe assumed case of increased tension of the metal core sheet). Decreasein metal core sheet tension would develop clockwise movement of the arm64 and retraction of the rod member 69 to result in deceleration of themotor 31.

As the coil 19 becomes totally unwound, the trailing edge of the metalsheet 20 passes sequentially through the present apparatus. When thetrailing edge of the sheet 20 passes the last set of drive rolls 29,which are driven by the tension-responsive drive means 31, there is nofurther means in the system for maintaining tension of the trailing edgeportion of the metal sheet 20. Accordingly the trailing edge of eachcoil 19 will frequently exhibit misalignment of the fibrous layers a,40b and the coated metal sheet 20a as the tension is released from themetal sheet 20a as the result of the trailing edge passing beyond therollers 29, 30. This misalignment appears only in the last few feet ofeach coil 27. The same misalignment has been found to occur frequentlywhen the back tension of the metal sheet 20a is relaxed for any reasonduring continuous production of protected metal sheets.

If desired, suitable position-locating means may be provided inassociation with the bonding rolls 26a or 26b or both. Suchposition-locating means may comprise: mechanical feeler members whichengage the side edge of the moving metal sheet 20a; or alight-beam-and-electric-eye combination which senses the location of theside edge of the advancing metal sheet 2001. The positionlocating meansis connected through suitable relays and control means to theaxis-determining apparatus of the crown roll 38. For example, theprecise location of the bearing blocks 51 (FIGURE 3) can be determinedautomatically in accordance with the instantaneous location of the sideedge of the moving metal sheet 20a or 20b as determined by suchposition-locating means. Thereby the metal sheet 20a is automaticallyguided over the crown roll 38 to registry with the fibrous sheets 40a,40b at the nip of the bonding rolls.

Throughout the present specification there has been reference tomaintaining a predetermined tension in the metal core sheet between thebonding rolls 26a, 26b and some point preceding the galvanazing pot 24.The exact quantum of tension has not been measured by applicants sincethe precise quantum has no real significance in the fabrication ofprotected metal sheets. Moreover the precise required tension has beendemonstrated to vary according to the gauge of metal sheets beingprocessed and also has even been shown to vary between successive coilsof sheet metal of the same gauge. The flatness or camber of eachindivdual coil of sheet metal may vary despite the same nominal gaugethickness of two coils. Hence the quantum of tension required to retaincontrol of the moving sheet may vary.

Operators of the protected metal fabricating apparatus quickly learn theneed for tension by observing the depression of the journals 57 (FIGURE8). Maintaining the journals depressed by one-inch may be satisfactoryfor one coil. Maintaining the journals 57 depressed byone-and-one-half-inches may be indicated for the succeeding sheet ofmetal. The precise tension in quantitative terms has never been measuredsince it has no reproducible utility on practicing this invention.

We claim:

1. In an apparatus for producing a building sheet of the characterhaving a metal core sheet and fibrous layers covering the surfaces ofthe core sheet and secured there to by thin layers of non-corrodiblemetal adhesive alloyed to the surfaces of the metal core sheet and keyedto the fibrous layers;

said apparatus comprising in sequence:

metal core sheet uncoiling apparatus, metal core sheet cleaning bathmeans, a molten bath containing the said metal adhesive, guide rollmeans engageable with the said metal core sheet, fibrous layer bondingroll means, and building sheet receiving means; said apparatus furtherincluding drive means for advancing the said metal core sheettherethrough;

the improvement comprising:

control means for locating the axis of the said guide roll means andmeans preceding the said molten bath for maintaining the said metal coresheet at predetermined tension when in engagement with the said guideroll means whereby the position of the said metal core sheet relative tothe said bonding roll means may be controlled by adjustment of the saidguide roll means.

2. The improvement of claim 1 wherein the said means for maintainingtension comprises a tension-measuringdevice engageable with the saidmetal sheet and connected in speed regulating relation with the saiddrive means whereby the speed of the said drive means is regulatedinversely to the deviation of tension from a predeter mined value.

3. The improvement of claim 1 wherein the said guide roll meanscomprises a crown roll which is maintained in contact with the bottomsurface of the said metal core sheet.

4. The improvement of claim 3 wherein the said crown roll hascircumferential surface grooves.

5. The improvement of claim 1 including positionlocating meansassociated with the said bonding roll means for determining the positionof the said metal core sheet between the said guide roll means and thesaid bonding roll means,

the said position-locating means being connected to the said guide rollmeans in axis-locating relation whereby the said axis of the said guideroll means may 7 be located automatically to maintain the position ofthe said metal core sheet substantially constant at the said bondingroll means.

6. In an apparatus for producing a building sheet of the characterhaving a metal core sheet and fibrous layers covering the surfaces ofthe core sheet and secured thereto by thin layers of non-corrodiblemetal adhesive alloyed to the surfaces of the metal core sheet and keyedto the fibrous layers;

said apparatus comprising in sequence:

means for uncoiling a coil of metal core sheet, coating means forapplying a molten adhesive to the said metal core sheet, compressiveroll mean for bonding fibrous layers to the said metal core sheet andfor fusing the said molten adhesive;

the improvement comprising:

control means for maintaining the said metal core sheet at apredetermined tension between the said compressive roll means and aselected point along the metal core sheet preceding the said coatingmeans.

References Cited by the Examiner UNITED STATES PATENTS Eichmann 228-28Ruhr 228-41 Coffman 156313 X Michel 24275.51 X Michel 7218 Nashley156164 Bendz 24275.51 X Snyder 24275.51 Coffman 29200 Franzmann 24275Daniels et a1 24275.51 Steckel et al 156164 Hubbell 29-473.1 Cotrman eta1. 29472.9 Lorig 29407 Cotfman 29473.1

JOHN F. CAMPBELL, Primary Examiner.

WHITMORE A. WILTZ, Examiner.

THOMAS H. EAGER, C. T. MOON,

Assistant Examiners.

1. IN AN APPARATUS FOR PRODUCING A BULIDING SHEET OF THE CHARACTERHAVING A METAL CORE SHEET AND FIBROUS LAYERS COVERING THE SURFACES OFTHE CORE SHEET AND SECURED THERETO BY THIN LAYERS OF NON-CORRODIBLEMETAL ADHESIVE ALLOYED TO THE SURFACES OF THE METAL CORE SHEET AND KEYEDTO THE FIBROUS LAYERS; SAID APPARATUS COMPRISING IN SEQUENCE: METAL CORESHEET UNCOILING APPARATUS, METAL CORE SHEET CLEANING BATH MEANS, AMOLTEN BATH CONTAINING THE SAID METAL ADHESIVE, GUIDE ROLL MEANSENGAGEABLE WITH THE SAID METAL CORE SHEET, FIBROUS LAYER BONDING ROLLMEANS, AND BUILDING SHEET RECEIVING MEANS; SAID APPARATUS FURTHERINCLUDING DRIVE MEANS FOR ADVANCING THE SAID METAL CORE SHEETTHERETHROUGH; THE IMPROVEMENT COMPRISING: